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Microchip Technology SMAJ4746E3/TR13
- Part No.:
- SMAJ4746E3/TR13
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ4746E3/TR13.pdf
- Description:
- DIODE ZENER 18V 2W DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,139
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Product details
Overview
SMAJ4746E3/TR13 from SM Semiconductor is a 18 V, 5% tolerance Zener diode in SMA (DO-214AC) package, rated for 2.0 W steady-state power dissipation, 14.0 Ω dynamic impedance at 14.0 mA test current, and 100 mA maximum reverse leakage at 13.7 V, used for overvoltage clamping in power supply regulation and I/O line protection.
For engineers reviewing the SMAJ4746E3/TR13 datasheet, SMAJ4746E3/TR13 pinout, SMAJ4746E3/TR13 application, or SMAJ4746E3/TR13 equivalent, key selection criteria include zener voltage tolerance, surge current capability (250 A), thermal resistance (25 °C/W), and ROHS-compliant matte-tin plating for reliable solderability in high-density PCB layouts.
Technical Context
This device operates as a silicon planar Zener diode with sharp breakdown knee, specified for stable voltage regulation across 1 mA to 100 mA operating current range and -65 °C to +150 °C temperature envelope. Its 18 V nominal breakdown voltage is measured at 14.0 mA (IZT), with 0.25 mA knee current (IZK) defining low-current conduction onset.
The SMAJ4746E3/TR13 features a void-free thermosetting epoxy case meeting UL94V-0 flammability rating, cathode band polarity marking, and 0.3 g mass. It delivers 250 A peak surge current under 1/2 sine wave (1/120 s) transient conditions per JEDEC standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18.0 V ±5% at 14.0 mA - defines precise clamping threshold for 15–21 V transient suppression |
| Power Dissipation (PM(AV)) | 2.0 W - supports continuous regulation without heatsink up to ambient 100 °C with 25 °C/W thermal resistance |
| Dynamic Impedance (ZZT) | 20.0 Ω at IZT - ensures minimal voltage shift under load variation during regulation |
| Peak Surge Current (Izsm) | 250 A - withstands high-energy transients like inductive switch-off spikes in automotive and industrial systems |
| Reverse Leakage (IR) | 5 µA max at 13.7 V - guarantees low standby power loss in always-on protection circuits |
| Thermal Resistance (RθJL) | 25 °C/W junction-to-lead - enables direct lead heat sinking for sustained pulse operation |
| Operating Temperature | -65 °C to +150 °C - validated for under-hood automotive, industrial control, and telecom infrastructure environments |
Pinout & Package
Package: SMA (DO-214AC), surface-mountable, void-free thermosetting epoxy case with cathode band marking and ROHS-compliant matte-tin terminals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias; reference node in reverse-bias clamping | Connected to lower-potential side of protected circuit; determines clamping polarity relative to cathode |
| Cathode | Current exit terminal in forward bias; high-impedance input in reverse bias until breakdown | Marked by band; tied to higher-potential rail (e.g., VCC or signal line) to clamp overvoltage to ground or rail |
Key Features
| Feature | Design Value |
|---|---|
| 5% Zener voltage tolerance | Enables tighter clamping window vs. 10% variants, reducing margin overhead in precision protection designs |
| UL94V-0 epoxy encapsulation | Provides flame-retardant mechanical integrity essential for safety-critical automotive and industrial assemblies |
| ROHS-compliant matte-tin plating | Ensures consistent wetting and joint reliability in lead-free reflow processes per MIL-STD-750 Method 2026 |
| 0.3 g mass and low-profile form factor | Minimizes board stress and supports automated placement in space-constrained consumer and telecom modules |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Clamping |
|---|---|
Use Scenario: Suppressing load-dump transients on 12 V battery-fed ECUs and body control modules. IC Role / Device Role / Timing Role: Zener-based shunt clamp placed between VBAT and ground to limit voltage excursion to ≤21 V. Use Value: Prevents damage to downstream 18 V-rated regulators and microcontrollers during ISO 7637-2 Pulse 5a events. | Use Scenario: Protecting analog outputs of pressure/temperature sensors interfacing with PLC analog inputs. IC Role / Device Role / Timing Role: Reverse-biased Zener connected across sensor output and ground to clamp ESD and switching noise. Use Value: Maintains signal fidelity below 13.7 V reverse standoff while surviving 250 A surge pulses per IEC 61000-4-5. |
| Consumer Device USB Port ESD Suppression | Telecom DC Power Input Stage |
Use Scenario: Secondary-level protection on USB VBUS lines against human-body-model (HBM) ESD events. IC Role / Device Role / Timing Role: Fast-response Zener placed after primary TVS array to absorb residual energy and stabilize clamping voltage. Use Value: Achieves <5 µA leakage at 13.7 V, preserving battery life while delivering 18 V precision clamping for USB 2.0 compliance. | Use Scenario: Front-end overvoltage protection for 24 V telecom power supplies feeding base station RF modules. IC Role / Device Role / Timing Role: Shunt regulator clamping input rail to 18 V during brownout recovery or rectifier overshoot. Use Value: Sustains 2.0 W continuous dissipation with 25 °C/W thermal resistance, enabling compact heatsinkless design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4746A | Same 18 V nominal voltage but 10% tolerance (vs. 5%) and DO-41 through-hole package | Lacks ROHS-compliant plating and UL94V-0 epoxy; unsuitable for SMT production or automotive AEC-Q200 requirements | Select only for legacy through-hole prototyping where cost outweighs precision and compliance |
| BZX84-C18 | 18 V, 5% tolerance, but 300 mW power rating and SOT-23 package; 10x lower surge current (25 A) | Insufficient for industrial surge immunity; limited to low-energy signal-line protection | Choose only for space-constrained signal-level clamping where 250 A surge capability is unnecessary |
Compared with 1N4746A and BZX84-C18, the SMAJ4746E3/TR13 uniquely combines 5% voltage tolerance, 2.0 W power handling, 250 A surge rating, and SMT-ready SMA packaging-making it the only option qualified for automotive-grade power rail clamping and industrial surge immunity standards.
Availability
SMAJ4746E3/TR13 is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface clamping, and telecom DC input stage applications requiring stable component supply, long-term lifecycle support, and ROHS-compliant manufacturing.
Supply support for SMAJ4746E3/TR13 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
SM Semiconductor is a Taiwan-based manufacturer specializing in discrete semiconductors, including Zener diodes, TVS devices, and rectifiers, with ISO 9001-certified production and global distribution.
The SMAJ series was designed specifically for high-reliability transient voltage suppression in automotive, industrial, and telecom power systems-emphasizing tight voltage tolerance, robust surge capability, and UL94V-0 safety compliance.
FAQ
What is the exact Zener voltage tolerance for SMAJ4746E3/TR13?
The SMAJ4746E3/TR13 has a ±5% Zener voltage tolerance, meaning its breakdown voltage is guaranteed between 17.1 V and 18.9 V at 14.0 mA test current. This tighter tolerance than standard 10% Zeners allows more precise clamping in sensitive power rails and reduces design margin overhead compared to wider-tolerance alternatives like SMAJ4746A.
Does SMAJ4746E3/TR13 meet ROHS and UL safety standards?
Yes, SMAJ4746E3/TR13 uses ROHS-compliant annealed matte-tin plating on terminals and a void-free thermosetting epoxy case certified to UL94V-0 flammability rating. These features ensure compatibility with lead-free reflow processes and satisfy safety requirements for automotive and industrial end equipment where flame resistance and environmental compliance are mandatory.
What is the maximum surge current rating for SMAJ4746E3/TR13?
The SMAJ4746E3/TR13 is rated for 250 A peak surge current under a 1/2 sine wave pulse of 1/120 second duration, per JEDEC test conditions. This rating reflects its ability to absorb high-energy transients such as inductive load switching spikes and lightning-induced surges in automotive and industrial power systems.
How does the thermal resistance of SMAJ4746E3/TR13 affect its power handling?
With a junction-to-lead thermal resistance of 25 °C/W, the SMAJ4746E3/TR13 can dissipate its full 2.0 W rating when leads are adequately heat-sunk-for example, using wide copper pours or thermal vias. Without external heat sinking, derating is required above 100 °C ambient to maintain safe junction temperature, making thermal layout critical in high-power transient scenarios.
Can SMAJ4746E3/TR13 be used as a direct replacement for SMAJ4746A?
No-SMAJ4746E3/TR13 and SMAJ4746A differ in voltage tolerance (5% vs. 10%), packaging (E3/TR13 denotes tape-and-reel with ROHS plating), and test documentation. While both share the same 18 V nominal voltage and SMA package, the tighter tolerance and compliance certification of SMAJ4746E3/TR13 make it unsuitable as a drop-in replacement unless the design explicitly requires those enhanced specifications.
SMAJ4746E3/TR13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±10%
- Power - Max:
- 2 W
- Impedance (Max) (Zzt):
- 20 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 13.7 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -55°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC
SMAJ4746E3/TR13 FAQ
1.How can I place an order for SMAJ4746E3/TR13 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ4746E3/TR13 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SMAJ4746E3/TR13 reliable?
The price and inventory of SMAJ4746E3/TR13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ4746E3/TR13 is usually 5 days.
3.What payment methods are accepted for SMAJ4746E3/TR13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ4746E3/TR13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ4746E3/TR13?
SMAJ4746E3/TR13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ4746E3/TR13 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SMAJ4746E3/TR13?
For technical support, including SMAJ4746E3/TR13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ4746E3/TR13 requirements.
6.How does Aetrix verify that SMAJ4746E3/TR13 is sourced from the original manufacturer or authorized distributors?
All SMAJ4746E3/TR13 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SMAJ4746E3/TR13 meets industry standards.
7.What is the process for return or replacement of SMAJ4746E3/TR13?
All SMAJ4746E3/TR13 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ4746E3/TR13, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SMAJ4746E3/TR13 part is unused and in its original packaging.
Return procedure for SMAJ4746E3/TR13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ4746E3/TR13 Tags
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MMBZ5240B-7-F
Diodes Incorporated
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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MMSZ4682T1G
onsemi
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BZT52C15S-7-F
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MM5Z5V1ST1G
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